When Ideas Have Sex.

Sex is what makes biological evolution cumulative, because it brings
together the genes of different individuals. A mutation that occurs in
one creature can therefore join forces with a mutation that occurs in
another. The analogy is most explicit in bacteria, which trade genes
without replicating at the same time – hence their ability to acquire
immunity to antibiotics from other species. If microbes had not begun
swapping genes a few billion years ago, and animals had not continued
doing so through sex, all the genes that make eyes could never had got
together in one animal; nor the genes to make legs or nerves or
brains. Each mutation would have remained isolated in its own linage,
unable to discover the joys of synergy. Think, in cartoon terms, of
one fish evolving a nascent lung, another nascent limb and neither
getting out on land. Evolution can happen without sex; but it is far,
far slower.
And so it is with culture. If culture consisted simply of learning
habits from others, it would soon stagnate. For culture to turn
cumulative, ideas needed to meet and mate. The ‘cross-fertilisation of
ideas’ is a cliché, but one with unintentional fecundity. ‘To create
is to recombine’ said the molecular biologist François Jacob. Imagine
if the man who invented the railway and the man who invented the
locomotive could never meet or speak to each other, even through third
parties. Paper and the printing press, the internet and the mobile
phone, coal and turbines, copper and tin, the wheel and steel,
software and hardware. I shall argue that there was a point in human
pre-history when big-brained, cultural, learning people for the first
time began to exchange things with each other, and that once they
started doing so, culture suddenly became cumulative, and the great
headlong experiment of human economic ‘progress’ began. Exchange is to
cultural evolution as sex is to biological evolution.
Matt Ridley